Rotor for impact crusher

ABSTRACT

An impact crusher is disclosed having a rotor with four hammers equally spaced around the periphery thereof. Two of the hammers, diametrically opposite each other, are each fitted in slots and have a leading hammer face of conventional radial length while the other two hammers are substantially shorter. The shorter hammers each comprise an integral formation with a spiral body extension that projects progressively farther radially outward beginning at the leading peripheral edge of one slot and reaching maximum outward projection at the back wall of the other slot. The two shorter hammers each have a leading surface having a flat portion substantially perpendicular to the periphery of the spiral body extension from which the flat portion projects, and terminates with a radially outer edge which traces a common circle with outermost edges of the two longer hammers. Each of such short hammers strikes, deflects and throws pieces of rock of a size which in the absence of such short hammers can slide along the periphery of the rotor from the trailing side of one long hammer to the leading hammer face of the other long hammer, and which if permitted to occur can result in the crusher discharging such pieces which may sometimes be more than three times the size the crusher is set to produce.

waited States Patent 1191 Lowe et all.

t 1111 tam am WIN/1W, 112, 11974 1 RUTGR FOR IMPACT CRUSHER [75] Inventors: Keith B. Lowe; William R. Gray,

both of Appleton, Wis.

[73] Assignee: Allis-Chalmers Corportion,

' Milwaukee, Wis.

[22] Filed: Jan. 16, 1974 [21] Applt No.: 433,883

Primary Examiner-Roy Lake Assistant Examiner-E. F. Desmond Attorney, Agent, or Firm--Arthur M. Streich [57] ABSTRACT An impact crusher is disclosed having a rotor with four hammers equally spaced around the periphery thereof. Two of the hammers, diametrically opposite each other, are each fitted in slots and have a leading hammer face of conventional radial length while the other two hammers are substantially shorter. The shorter hammers each comprise an integral formation with a spiral body extension that projects progressively farther radially outward beginning at the leading peripheral edge of one slot and reaching maximum outward projection at the back wall of the other slot. The two shorter hammers each have a leading surface having'a flat portion substantially perpendicular to the periphery of the spiral body extension from which the flat portion projects, and terminates with a radially outer edge which traces a common circle with outermost edges of the two longer hammers. Each of such short hammers strikes, deflects and throws pieces of rock of a size which in the absence of such short hammers can slide along the periphery of the rotor from the trailing side of one long hammer to the leading hammer face of the other long hammer, and which if permitted to occur can result in the crusher discharg ing such pieces which may sometimes be more than three times the size the crusher is set to produce.

4 Claims, 2 Drawing Figures j ROTOR FOR IMPACT CRlUSllllER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to impact crushers which have a rotor carrying hammers arranged to strike and throw rock to disintegrate upon impact with target members spaced from the rotor, and in particular to an improved rotor for such a crusher.

2. Description of the Prior Art It has been long known to those familiar with the field of this invention, that impact crushers have been provided with rotors carrying two, three, four and even as many as six hammersspaced around the periphery of a rotor body. Examples of U.S. Pats. showing such rotors include No. 2,618,438 of Nov. 18, 1952 and No. 3,202,368 of 1965 which show two hammer rotors; No. 3,146,961 of Sept. 1, 1964 which shows a three hammer rotor; No. 1,864,973 of June 28, 1932 which shows a four hammer rotor; and No. 1,120,250 of Dec. 8, 1914 which shows a six hammer rotor.

It is also a known design to mount hammers in slots in a rotor body having a generally spiral body extension projecting progressively farther radially outward beginning at the leading peripheral edge of one slot and reaching maximum radial projection at the trailing edge of the next slot spaced in the direction of rotor rotation. Such designs provide a massive bodyportion backing each hammer along its entire radial length while its leading face is exposed to strike input mate rial. Of the aforementioned prior art patents, both patens showing two hammer rotors and the patentshowing a three hammer rotor, utilize rotorshaving such spiral extensions. i

It is also known that with such rotors as have such spiral extensions, oversize pieces of rock sometimes bounce back from targetbreaker bars and land on the rotor body immediately behind a hammer. Such-a piece may slide along the outer surface of the spiral body extension until it arrives at the leading hammer face of the following hammer. However, the relative motion of such a sliding piece engaging such a hammer face may be such that the piece is pocketed and carried by the hammer around the rotor and through the machine rather than being struck and thrown back at the target breaker bars. Byway of example, a machine having hammers with a radial dimension of perhaps 5.0 inches, may have adjustable breaker bars set so the machine produces 1.5 inch diameter particles. In such a 'machine a particle 5.0 inches in diameter may slide along the spiral body extension and come in contact with the 5.0 inch hammer face, and be caught and'carried through the machine, rather than being struck and thrown again at the target breaker bars. Thus, a machine adjusted toproduce 1.5 inches of material can and sometimes does discharge 5.0 inches of material.

In the past when the foregoing problem has occurred shown in US. Pat. No. 2,862,669 of Dec. 2, 1958.

SUMMARY OF THE PRESENT INVENTION An improved solution to the aforesaid problem that has been associated with such prior artmachines, is the primary object of the present invention.

According to a preferred embodiment of the present invention an impact crusher rotor is provided with four hammers equally spaced around the periphery thereof. Two of the hammers, diametrically opposite each other, are each fitted in slots and have a leading hammer face of conventional radial length while the other two hammers are substantially shorter. The shorter hammers each comprise an integral formation with. a spiral body extension that projects progressively farther radially outward beginning at the leading peripheral edge of one slot and reaching maximum outward projection at the back wall of the other slot. The two shorter hammers each have a leading surface having a flat portion substantially perpendicular to the periphery of the spiral body extension from which the flat portion projects, and terminates with a radially outer edge which traces a common circle with outermost edges of the two longer hammers. Each of such short hammers strikes, deflects and throws pieces of rock of a size which in the absence of such short hammers can slide along the periphery of the rotorfrom the trailing side of one long hammer to the leading hammer face of the other long hammer, and which if permitted to occur canresult in the crusher discharging such pieces which may sometimes be'more than three times the size the BRIEFODESCRIPITION or THE DRAWING FIG. 1 of the drawing is a view in elevation and partly in section, showing an impact crusher according to the present invention; and

FIG. 2 is aperspective view of a rotor for the crusher shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, an impact crusher is shown which comprises a housing 1 having disposed within a lower area thereof a rotor 2 mounted on a shaft 3 which is carried by suitable journal bearings 4. The housing 1 defines a material feed opening 5 over a feed chute 6 inclined downwardly toward the rotor 2. The feed chute 6 delivers rock to hammers 7 through 10 which are carried by the rotor 2 in a manner which will hereinafter be described in detail.

'Chute 6 directs feed rock to rotor 2 at a location where its hammers 7-10 are ascending with the result that the impact of hammers 7-10 on rock breaks the rock into smaller particles which are thrown upwardly tobreak into even smaller particles upon impact with a complement of primary target breaker bars 12 and 13 which are carried by the casing 1.. A secondary crushing occurs when such particles drop downwardly from bars 12 and 113 to be again struck by hammers 7-ll0 and thrown toward a discharge area 14 where the particles impact with a vertical array of secondary target bars 15. Close to the periphery of rotor 2, one or more adranged. Adjustable and yieldable mounts such as for bars 16, 16' are well known and one example of such mounts is shown in US. Pat. No. 2,486,421 of Nov. 1, 1949. Any particles not passing between the bars and into discharge area 14, progress downwardly toward the bar 16 where such particles are subjected to a final crushing as the particles are nipped and urged through the space between rotor 2 and bar 16' to the lowest portion of the discharge area. The casing 1 may include a pivotal portion 18 connected to base structure 19 by a hinge 20, operative to open the casing and provide access to the internal mechanisms.

The rotor 2, shown in elevation in FIG. 1 and perspective in FIG. 2, will now be described. Although the rotor 2 may be made up of a number of disc-like portions 21, 22 shown in FIG. 2, the rotor may alsobe thought of as comprising an elongated central body portion 23 with a pair of axially extending slots 24, 25,

and a pair of diametrically opposed spiral body extensions 26, 27. The body extensions 26, 27 each project progressively farther radially outward beginning at a leading peripheral edge 28 of one slot and reaching maximum radial projection. at a terminusdefming a face 30 planar with a back wall 32 of the other. slot.

First and second hammer means, shown asthe hammer bars 7 and 8, are each arranged in one of the slots 24, 25, and project outwardly of such slots with a leading hammer face 34 extending outwardly and terminating with an edge 35 outward of slot edge 28 at least as far as the radially outer edge of the face 30.

Third and fourth hammer means, shown as the hammers 9 and 10 and substantially shorter than hammers 7 and 8, are located diametrically opposite each other and midway between hammer bars 7 and 8. The hammers 9' and 10 each comprise an integral formation with one of thespiral body extensions 26, 27; that is,

hammer 9 projects outwardly from a midportion of extension 26 and hammer 10 projects outwardly from a midportion of extension 27.

With particular reference to FIG. 1, it can be seen thatthe hammers 9 and 10 each have a leading surface with a flat portion 40 substantially perpendicular to the periphery'of the spiral portion 26, 27 from which it projects, and the flat portion 40 terminates with an outer edge 41. The outer edge 41 may be formed by welding a rod of wear resistant material, such as manganese, to each of the hammers 9 and 10. The hammers 9 and 10 are formed so that upon rotation of rotor 2, the edges of hammers 7 and 8, and the edges 41 of hammers 9 and 10, trace a common circle about shaft 3. Since all four hammers reach out to a common circle, and since hammers 9 and 10 project outwardly of a location midway out on spiral extensions 26, 27, it of course means that hammers 9 and 10 have hammer faces much shorter than the hammer faces 34 of hammers 7 and 8.

In the operation of the described impact crusher having the rotor 2 according to the present invention and bars l6, 16 set to discharge 1.5 inches of material, all

served that material struck by a long hammer, such as,

hammer 7, sometimes breaks to produce a particle two or three times the size of the 1.5 inch gap set between the rotating hammers and the adjustable bar 16, with such gap representing the desired size of discharged product. Such a larger particle, of perhaps 4 or 5 inches diameter, rebounding from a target bar toward rotor 2 sometimes lands on the periphery of spiral body extension 27 and slides along this surface toward the relatively large pocket 42 defined by the;close in end of spiral extension 27 at the slot edge 28 and hammer 8. A 4 or 5 inch particle, if it can slide into pocket 42 and be carried around the axis of shaft 3, would not project beyond the outer end of hammer 8 and therefore would not make contact with the lower adjustable bar 16'. A short hammer such as hammer 10, acts to intercept such a particle headed for pocket 42. The surface 40, being perpendicular to the spiral surface, rather than radiating from shaft 3, and shorter than pocket $2, insures that such an intercepted 4 or 5 inch particle will extend outwardly of edge 41 and move outwardly along surface 40. Such a particle cannot attempt to turn to again follow a circumferential path again until it passes beyond the edge 41. But since the edge 41 is the outermost line of the short surface 40 and traces the same circle as the edge 35 of the following hammer 8, it is much more likely to give a 4 or 5 inch particle a trajectory and velocity that will result in the particle clearing pocket 42 and being subjected to further blows and impacts rather than the particle being caught in pocket 42 and carried through the gap with breaker bar 16'.

From the foregoing detailed description of the present invention it has been shown how the objects of the present invention have been attained in a preferred maner. However, modification and equivalents of the disclosed concepts such as readily occur to those skilled in the art are intended to be included in the scope of this invention. Thus, the scope of the inven tion is intended to be limited only by the scope of the claims such as are or may hereafter be, appended hereto.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A four hammer rotor for an impact crusher having a housing enclosing and supporting the rotor, a drive .for turning the topof the rotor away from a material inlet opening in the housing, and target members spaced from the rotor opposite the inlet opening for disintegrating input material struck and thrown by the hammers to impact against the target members, with said rotor comprising: i

a. an elongated central body portion with a pair of axially extending peripheral slots diametrically opposite each other and two diametrically opposed generally spiral body extensions each projecting progressively farther radially outward beginning at a location which is ahead of one slot in the direction of rotor rotation and reaches maximum radial projection at a terminus defining a face planar with the back wall of the other slot;

b. first and second hammer means each comprising a bar arranged in one of said slots and projectng outwardly thereof with a leading hammer face extending outwardly at least as far as the radially outer edge'of said planar face; and

c. third and fourth hammer means located diametrically opposite each other and between the first and second hammer means, and with each of said third and fourth hammer means projecting from one of the rotor body spiral extensions with a leading surface radially shorter than the hammer faces of the first and second hammer means and having a flat portion substantially perpendicular to the periphery of the spiral extenson, and with the flat portion terminating with a radially outer edge which traces a common circle with radially outer edges of the first and second hammer means upon rotation of the rotor.

2. A rotor according to claim 1 in which the location from which the progressively farther projection of each generally spiral body extension begins, is at the leading peripheral edge of the said one slot, and the said third and fourth hammer means each project from the midportion of one of the rotor body spiral extensions.

3. A rotor according to claim 2 in which said third and fourth hammer means each comprise an integral formaton with the spiral body extension from which it projects.

4. A rotor according to claim 3 in which said radially outer edge of the third and fourth hammer means is a wear resistant bar welded thereto in the plane of the flat portion of the leading surface of each of the said third and fourth hammer means. 

1. A four hammer rotor for an impact crusher having a housing enclosing and supporting the rotor, a drive for turning the top of the rotor away from a material inlet opening in the housing, and target members spaced from the rotor opposite the inlet opening for disintegrating input material struck and thrown by the hammers to impact against the target members, with said rotor comprising: a. an elongated central body portion with a pair of axially extending peripheral slots diametrically opposite each other and two diametrically opposed generally spiral body extensions each projecting progressively farther radially outward beginning at a location which is ahead of one slot in the direction of rotor rotation and reaches maximum radial projection at a terminus defining a face planar with the back wall of the other slot; b. first and second hammer means each comprising a bar arranged in one of said slots and projectng outwardly thereof with a leading hammer face extending outwardly at least as far as the radially outer edge of said planar face; and c. third and fourth hammer means located diametrically opposite each other and between the first and second hammer means, and with each of said third and fourth hammer means projecting from one of the rotor body spiral extensions with a leading surface radially shorter than the hammer faces of the first and second hammer means and having a flat portion substantially perpendicular to the periphery of the spiral extenson, and with the flat portion terminating with a radially outer edge which traces a common circle with radially outer edges of the first and second hammer means upon rotation of the rotor.
 2. A rotor according to claim 1 in which the location from which the progressively farther projection of each generally spiral body extension begins, is at the leading peripheral edge of the saiD one slot, and the said third and fourth hammer means each project from the midportion of one of the rotor body spiral extensions.
 3. A rotor according to claim 2 in which said third and fourth hammer means each comprise an integral formaton with the spiral body extension from which it projects.
 4. A rotor according to claim 3 in which said radially outer edge of the third and fourth hammer means is a wear resistant bar welded thereto in the plane of the flat portion of the leading surface of each of the said third and fourth hammer means. 